The present invention relates to battery chargers and, more particularly, to an improved battery charger and battery charging circuit.
A typical battery charger includes a battery charging circuit which is connectable to a power source and to a rechargeable battery and which is operable to charge the battery.
One of the problems with some existing battery chargers is that the battery charging circuit does not operate continuously on different sources of AC power.
Another problem with some existing battery chargers is that the battery charging circuit does not provide charge current to the batteries as efficiently as possible.
A further problem with some existing battery chargers is that some battery chargers are not able to charge both Nickel-cadmium (NiCd) and Nickel-Metal Hydride (NiMH) batteries.
Yet another problem with some existing battery chargers is that, in order to charge both types of Nickel battery chemistries, these battery chargers require special identification components.
Another problem with existing battery chargers is that the battery charging circuit does not shut down if one of the components of the battery charging circuit fails or malfunctions. Specifically, some other existing battery chargers utilize topologies in which charge and control components are separate. In such existing chargers, a single failure on the printed circuit board or battery could result in uncontrolled charge and, thus, overcharging.
A further problem with existing battery chargers is that a separate low voltage supply is required to control the battery charging circuit.
Yet another problem with some existing battery chargers is that several separate components and circuits are necessary to perform the required functions of the battery charger, increasing the cost and complexity of the battery charger.
The present invention provides a battery charger that alleviates the problems with existing battery chargers. The invention provides a battery charger for charging different types of batteries and capable of operating on alternate sources of AC power or on alternate sources of DC power. Also, the invention provides a battery charging circuit which will not operate if one of the power source, the battery, the power switch means and the control means (including the microcontroller) malfunctions. In addition, the invention provides a battery charging circuit in which the battery under charge enables the circuit and, in some embodiments, powers the microcontroller. The battery charging circuit operates even if the battery under charge is in a low or depleted state (i.e., the battery is in a depleted state).
In one aspect, the invention provides a battery charger comprising a battery charging circuit electrically connectable to a power source and to a battery and operable to charge the battery, the circuit including power switch means operable to provide power from the power source to charge the battery, and control means for operating the circuit, the control means being electrically connected to the circuit and providing a control signal to the power switch means to control the power switch means, the power source, the battery, the power switch means and the control means being electrically connectable by the circuit so that, when one of the power source, the battery, the power switch means and the control means malfunctions, the circuit does not operate to charge the battery. Preferably, the circuit electrically connects the power source, the battery, the power switch means and the control means in series.
In another aspect, the invention provides a method of charging a battery, the method comprising the acts of providing the battery charger, connecting the battery charger to the power source, connecting the battery to the battery charger, electrically connecting the power source, the battery, the power switch means and the microcontroller so that, when the battery is connected to the circuit, if one of the power source, the battery, the power switch means and the microcontroller malfunctions, the circuit will not operate to charge the battery, charging the battery, monitoring the circuit to determine when one of the power source, the battery, the power switch means and the microcontroller malfunctions, and, if one of the power source, the battery, the power switch means and the microcontroller malfunctions, preventing the circuit from charging the battery. Preferably, the act of electrically connecting the power source, the battery, the power switch means and the microcontroller includes electrically connecting the power source, the battery, the power switch means and the control means in series.
In a further aspect, the invention provides a battery charger comprising a battery charging circuit connectable to a power source and to a battery and operable to charge the battery, and a microcontroller electrically connected to and for operating the circuit.
In another aspect, the invention provides a battery charger comprising a battery charging circuit operable to power a battery when the battery is connected to the circuit such that the battery enables the circuit.
In yet another aspect, the invention provides a method for operating the battery charger, the method comprising the acts of providing a battery, connecting the battery to the battery charging circuit, and supplying power from the battery to the microcontroller to operate the microcontroller.
In another aspect, the invention provides a software program for operating the battery charger.
One advantage of the present invention is that the battery charger will operate continuously on alternate sources of AC power, such as alternators, generators, inverters and welders.
Another advantage of the present invention is that the battery charging circuit provides charge current to the batteries as efficiently as possible.
A further advantage of the present invention is that the battery charger is able to charge both types of Nickel battery chemistries in the same charger.
Yet another advantage of the present invention is that the battery charger is able to charge both types of Nickel battery chemistries without any special identification schemes and/or electronic components.
Another advantage of the present invention is that the power supply, power switch means, battery and microcontroller are connected in a circuit such that, if any one of these components fails, the battery charging circuit will shut down.
A further advantage of the present invention is that the battery being charged provides power to the low voltage supply which, in turn, enables the battery charging circuit.
Yet another advantage of the present invention is that the microcontroller includes integrated components which perform many of the required functions of the battery charger, reducing the cost and complexity of the battery charger.
Other features and advantages of the invention will become apparent to those skilled in the art upon review of the following detailed description, claims and drawings.